［２００分］在jsp页面如何生成图片的校验码，用于用户的登陆校验!!急等
在jsp页面如何生成图片的校验码，用于用户的登陆校验!!急等
最好有现成的代码！如果可以另开100分的一帖！！！
[解决办法]
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletException;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;
import java.io.IOException;
/**
* @author <a href= "mailto:jade_yuan@hotmail.com "> Jade Yuan </a>
* @version 2006-3-9 18:34:36
*/
public class ImageServlet extends HttpServlet {
private static final String CONTENT_TYPE = "image/jpeg ";
// private static final String [] FontNames={ "SansSerif ", "Serif ", "MonoSpaced ", "Dialog ", "DialogInput "};
//Initialize global variables
public void init() throws ServletException {
}
//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
response.setContentType(CONTENT_TYPE);
response.setHeader( "Pragma ", "no-cache ");
response.setHeader( "Cache-Control ", "no-cache ");
response.setDateHeader( "Expires ", 0);
// 在内存中创建图象
int width = 60, height = 20;
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.createGraphics();
//生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
//设定字体
g.setFont(new Font( "DialogInput ", Font.ITALIC, 18));
// g.setFont(new Font(FontNames[random.nextInt(6)%5], Font.ITALIC, 18));
//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);
// 随机产生255条干扰线，使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160, 200));
for (int i = 0; i < 255; i++) {
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x, y, x + xl, y + yl);
}
// 取随机产生的认证码(4位数字)
//String rand = request.getParameter( "rand ");
//rand = rand.substring(0,rand.indexOf( ". "));
String sRand = " ";
for (int i = 0; i < 4; i++) {
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
// 将认证码显示到图象中
g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110),
20 + random.nextInt(110))); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.drawString(rand, 13 * i + 6, 16);
}
//System.out.println( "validate code= " + sRand);
// 将认证码存入SESSION
HttpSession session = request.getSession();
session.setAttribute( "rand ", sRand);
// 图象生效
g.dispose();
// 输出图象到页面
ServletOutputStream outputstream = response.getOutputStream();
ImageIO.write(image, "JPEG ", outputstream);
}
//Clean up resources
public void destroy() {
}
Color getRandColor(int fc, int bc) { //给定范围获得随机颜色
Random random = new Random();
if (fc > 255) {
fc = 255;
}
if (bc > 255) {
bc = 255;
}
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
public static void main(String[] args) {
}
}
[解决办法]
<%@ page contentType= "image/jpeg " import= "java.awt.*,
java.awt.image.*,java.util.*,javax.imageio.* " %>
<%!
Color getRandColor(int fc,int bc){//给定范围获得随机颜色
Random random = new Random();
if(fc> 255) fc=255;
if(bc> 255) bc=255;
int r=fc+random.nextInt(bc-fc);
int g=fc+random.nextInt(bc-fc);
int b=fc+random.nextInt(bc-fc);
return new Color(r,g,b);
}
%>
<%
//设置页面不缓存
response.setHeader( "Pragma ", "No-cache ");
response.setHeader( "Cache-Control ", "no-cache ");
response.setDateHeader( "Expires ", 0);
// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
//生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);
//设定字体
g.setFont(new Font( "Times New Roman ",Font.PLAIN,18));
//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);
// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160,200));
for (int i=0;i <155;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x,y,x+xl,y+yl);
}
// 取随机产生的认证码(4位数字)
String sRand= " ";
for (int i=0;i <4;i++){
String rand=String.valueOf(random.nextInt(10));
sRand+=rand;
// 将认证码显示到图象中
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
g.drawString(rand,13*i+6,16);
}
// 将认证码存入SESSION
session.setAttribute( "rand ",sRand);
// 图象生效
g.dispose();
// 输出图象到页面
ImageIO.write(image, "JPEG ", response.getOutputStream());
%>
保存为images.jsp
再在文件中调用就行了
<input name=rand type=text value= " " size= "10 " maxlength=4> <img border=0 src= "images.jsp ">
<%
String rand = (String)session.getAttribute( "rand ");
//在images.jsp里已经把rand存入SESSION了，这里调用就行
String input = request.getParameter( "rand ");
if (rand.equals(input))
{
//你想进行的操作
}
else
{
String pstr= " <script language= 'javascript '> alert( '验证码输入错误，请重新输入! '); ";
pstr = pstr + " </script> ";
out.println(pstr);
}
%>
[解决办法]
<%! String sVerifyCode; //验证码字符串 %>
<%//设置页面不缓存
response.setHeader( "Pragma ", "No-cache ");
response.setHeader( "Cache-Control ", "no-cache ");
response.setDateHeader( "Expires ", 0);
response.reset();
try{
// 将认证码存入SESSION
//调用 runVerifyCode(int i) ,把i改成所要的验证码位数
VerifyCode VC = new VerifyCode();
session.setAttribute( "VerifyCode ",VC.runVerifyCode(4));
//session.setMaxInactiveInterval(60);
// 输出图象到页面
sVerifyCode = (String)session.getAttribute( "VerifyCode ");
OutputStream outs = response.getOutputStream();
ImageIO.write(VC.CreateImage(sVerifyCode), "JPEG ",outs);
}catch(Exception e){
return;
}
%>
代码如下
import java.awt.*;//导入类
import java.awt.image.*;
import java.util.*;
import javax.imageio.*;
public class VerifyCode {
static Random r = new Random();
static String ssource = "ABCDEFGHIJKLMNOPQRSTUVWXYZ " + "abcdefghijklmnopqrstuvwxyz " + "0123456789 ";
static char[] src = ssource.toCharArray();
//产生随机字符串
private static String randString (int length){
char[] buf = new char[length];
int rnd;
for(int i=0;i <length;i++){
rnd = Math.abs(r.nextInt()) % src.length;
buf[i] = src[rnd];
}
return new String(buf);
}
//调用该方法，产生随机字符串,
//参数i: 为字符串的长度
public String runVerifyCode(int i){
String VerifyCode = randString(i);
return VerifyCode;
}
//给定范围获得随机颜色
public Color getRandColor(int fc,int bc)
{
Random random = new Random();
if(fc> 255) fc=255;
if(bc> 255) bc=255;
int r=fc+random.nextInt(bc-fc);
int g=fc+random.nextInt(bc-fc);
int b=fc+random.nextInt(bc-fc);
return new Color(r,g,b);
}
//调用该方法将得到的验证码生成图象
//sCode:传递验证码 w:图象宽度 h:图象高度
public BufferedImage CreateImage(String sCode)
{
try{
//字符的字体
Font CodeFont = new Font( "Arial Black ",Font.PLAIN,16);
int iLength = sCode.length();//得到验证码长度
int width=22*iLength, height=20;//图象宽度与高度
int CharWidth = (int)(width-24)/iLength;//字符距左边宽度
int CharHeight = 16; //字符距上边高度
// 在内存中创建图象
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
//生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200,240));
g.fillRect(0, 0, width, height);
//设定字体
g.setFont(CodeFont);
//画随机颜色的边框
g.setColor(getRandColor(10,50));
g.drawRect(0,0,width-1,height-1);
// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160,200));
for (int i=0;i <155;i++)
{
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x,y,x+xl,y+yl);
}
for (int i=0;i <iLength;i++)
{
String rand = sCode.substring(i,i+1);
// 将认证码显示到图象中
g.setColor(new Color(20+random.nextInt(60),20+random.nextInt(120),20+random.nextInt(180)));
g.drawString(rand,CharWidth*i+14,CharHeight);
}
// 图象生效
g.dispose();
return image;
}catch(Exception e){
//e.printStackTrace();
//System.out.println(e.getMessage());
}
return null;
}
//测试
public static void main(String[] args){
//VerifyCode vc = new VerifyCode();
//String s1 = vc.runVerifyCode(4);
//Fun.DreamNewsTitle;System.out.println(s1);
//Image im = vc.CreateImage(s1);
//Graphics g = im.getGraphics();
//g.drawImage(im,20,20,this);
//g.drawString(s1,20,20);
}
}
